SB2026080633 - Remote denial of service in Cisco IOS XE XMCP protocol
Published: August 6, 2026
Security Bulletin ID
SB2026080633
CSH Severity
Medium
Patch available
YES
Number of vulnerabilities
1
Exploitation vector
Remote access
Highest impact
Denial of service
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 1 vulnerability.
1) Unchecked Input for Loop Condition (CVE-ID: CVE-2026-20301)
CWE-ID: CWE-606 - Unchecked Input for Loop Condition
CVSSv4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
The vulnerability allows a remote attacker to cause a denial of service.
The vulnerability exists due to improper handling of malformed packets in the Extensible Messaging Client Protocol (XMCP) when processing XMCP traffic. A remote attacker can send a malformed XMCP packet to cause a denial of service.
Only devices with the XMCP Server feature enabled are vulnerable.
Remediation
Install update from vendor's website.